Conformidade da água de abastecimento de Campina Grande (PB) com o padrão de aceitação para o consumo humano.

Abstract

This study aimed to verify compliances and non-compliances of the water indicators, aluminum, chloride, hardness, iron, manganese and turbidity with the standard of acceptance for human consumption, according Brazilian Ministry of Health Ordinance 518/2004, of water distributed at pressure zones A and B of water network of Campina Grande (7°13'50" S and 35°52'52"W), Paraiba state, northeast Brazil. Samples from six monitoring points were collected at three distinct times within the daily cycle from March to December 2009. These points were chosen according the criteria established in the National Guidance for the Sampling Plan on Health Surveillance related with water quality for human consumption. The application of one-factor analysis of variance (ANOVA) to the various data sets from monitoring of a same variable demonstrated that variations in the behavior of indicators were dependent on the position of sampling point rather than on time collection. From all indicators analyzed only aluminium (62.12%) and turbidity (3.42%) presented noncompliances with the already mentioned standard for human consumption acceptance, being these non-compliances related with both changes in raw water stored at the reservoir in rainy season and a water treatment plant operation schedule without flexibility to work with those changes. Ordinarily, none coagulation chemical agent is used during dry season, but from the beginning of rainy season aluminium sulphate is dosed in order to face up the significant increase on turbidity in raw water. But, without a rigorous control of factors which promote an optimal clarification, coagulant dosage tend to overlap its real demand and leave a residue of aluminium in the water which is more than the standardized maximum permissible concentration of 0.2mgAI/L.